Colorists to the stars tell us which blondes, brunettes, redheads and raven-haired ladies in Hollywood have the most beautiful hair color -- and how you can copy it

Why it works:
"The highlights add dimension, warmth and softness to their dark hair," says John. This hair color draws out their eyes, adds Cunningham, "the rich browns in the highlights match incredibly with the shine and sparkle of their brown eyes."